1. Field of the Invention
The present invention relates to a light emitting device with a resistance-configurable electrode.
2. Description of the Related Art
Referring to FIGS. 1 and 2, a conventional light emitting device 1 includes a first substrate 11, a second substrate 12, a light emitting unit 13 and electrodes 14.
The first substrate 11 and the second substrate 12 are spaced apart from each other and cooperate with a surrounding wall connected therebetween to define an inner space 101. The light emitting unit 13 is an organic light emitting diode (OLED) and is disposed in the inner space 101. The light emitting unit 13 is operable to emit light through at least one of the first and second substrates 11, 12, usually the first substrate 11, when electricity is supplied thereto. Each electrode 14 is a rectangular film, and has one end electrically connected to the light emitting unit 13 and the other end that extends outwardly of the inner space 101 along a surface of the first substrate 11 and that is adapted to be electrically connected to an electric power source (not shown).
However, light emitting characteristics of the light emitting units 13 may vary among different light emitting devices 1. Therefore, when a plurality of the conventional light emitting devices 1 are assembled in a same apparatus to form a product such as a lamp, the lamp may provide uneven brightness.
Two possible approaches are often employed to address the aforesaid problem. In one approach, each of the light emitting devices 1 is provided with an independent electric power source, and voltage of each electric power source is adjusted to result in uniform illumination of the light emitting devices 1. In another approach, each of the light emitting devices 1 is provided with an independent adjustable resistor, the resistance of which is adjustable to adjust the voltage fed to the respective light emitting unit 13, thereby making it possible for the light emitting devices 1 to emit uniform brightness.
Nevertheless, providing the light emitting devices 1 with independent electric power sources and/or independent adjustable resistors may increase a size of the apparatus and incur higher manufacturing cost.